Couplings for hoses to metal tubes or nipples having roughened surfaces including ribs, grooves and projections, together with surrounding ferrules with flanges abutting beads are well known in the art as shown by the following U.S. Pat. Nos.
______________________________________ Edelmann 2,430,921 November 18, 1947 Macleod 3,017,203 January 16, 1962 ______________________________________
Nipples having ribs, grooves, and barbs are also well known as shown in the following U.S. Pat. Nos.:
______________________________________ Cooper 567,962 September 22, 1896 Browne 884,461 April 14, 1908 Weinke 1,974,635 September 25, 1934 Davis et al 2,005,613 June 18, 1935 Jorgensen 2,066,473 January 5, 1937 Goodall 2,139,745 December 13, 1938 Kreidel 2,230,115 January 28, 1941 Main et al 2,371,971 March 20, 1945 Cline et al 2,805,088 September 3, 1957 Press 3,237,974 March 1, 1966 Kish 2,526,416 September 1, 1970 Luckenbill 3,596,933 August 3, 1971 Dudek 3,907,342 September 23, 1975 Washkewicz et al 3,966,238 June 29, 1976 Szentmihaly August 15, 1978 Kish 4,114,656 September 19, 1978 ______________________________________
However, most of these roughened surfaces are machined and formed by the removal of metal forming chips which are not acceptable in hose couplings for air conditioning units in which high pressures and temperatures of both liquids and gases are involved.
Ferrules for surrounding the sections of such hose portions engaging nipples are also well known, which ferrules are provided with end flanges which engage beads on or the tubes of the nipples as shown by the following U.S. Pat. Nos.
______________________________________ Boyle 2,109,522 March 1, 1938 Fisher et al 2,401,921 June 11, 1946 Doerr 2,481,730 September 13, 1949 Paquin 2,570,477 October 9, 1951 Spender et al 2,631,047 March 10, 1953 Nicol 3,345,091 October 3, 1967 Charbonnet 3,371,408 March 5, 1968 Kish 3,530,900 September 29, 1970 Mingo October 5, 1971 Frank 3,924,883 December 9, 1975 ______________________________________
It has been found that the machined ribs, ridges, barbs and/or projections on the nipple portions have, under flexing, vibration, and changes in pressure, caused cutting of the hose and leakage out through the linings and plies of the hose to the end of the hose. The exposed ends of the hose also are often attacked by the oils and greases which occur in the surroundings of the machines with which these hose couplings are used.
Furthermore, in order to seal the ends of the hose with a ferrule having an inwardly extending flange, these flanges previously have been welded to the nipple section. Then in order to assemble the hose into the annular cavities provided by the nipple and ferrule, special machinery is required.